Economic analysis of the treatment and prevention of drug use and abuse is essential for maximizing the public health benefit of expenditures on those interventions and treatments. The tools of medical decision making and statistical decision theory are potentially quite useful in research on drug use and abuse but have not been utilized. The overarching goal of this application is to tailor and apply those tools to the treatment and prevention of drug use and abuse. This project has two specific aims: 1. To develop MDM models for three substantive areas of importance to the prevention and treatment of drug use and abuse: (a) the treatment of attention deficit disorders, which are frequently comorbid with drug use;(b) screening and treatment of young children at risk for drug use and abuse and of other long-term behavior problems;and (c) the use of drug courts for juvenile offenders. For each area of application, we will (i) specify a MDM model linking the problems to proximal outcomes that shape key long-term outcomes for children;(ii) draw on relevant literature and expert opinion to develop estimates of the parameters of those models;(iii) model the cost-effectiveness of alternative treatments;and (iv) use a value of information analysis (VOI) to prioritize future research. 2. To encourage the use of these methods among substance use and abuse researchers through peer-reviewed journals in the field;relevant conferences;training activities for and consultation with other researchers and the center's web site. This work will focus not only on disseminating the substantive findings of our models but also on making the technical tools on which they are based more widely accessible to applied researchers.